Tuesday, April 21, 2009

Carbon Paper As A Form Copier

There are many ways of duplicating forms but none is as handy versatile as carbon paper. There are two primary types of carbon, class' by the action they encounter: 

   1. Glide action carbon inserted between a set of forms allows the action of the pencil (or ballpoint) to transfer dye to the surface of the sheet beneath.

   2. Hammer action carbon is used in typewriters and line printers of computers. The hammer action of the key(s) transfers the carbon coating to the sheet beneath. 

        Various methods of transferring, impressions between copies are also used:
   1. One-time carbon. Made of inexpensive Kraftex paper, it is interleaved between two sheets in the form, used once, and then thrown away. It is the most cost effective (also the messiest) method for multipart forms.
   2. Carbon-backed paper. The back of each form copy is coated with carbon, which transfers data to the copy beneath
   3. NCR (no carbon required) paper. The top sheet is chemically treated with invisible dye, which allows impressions to be transferred to the next lower copy. It is the cleanest method of copying but also the costliest. Erasing removes the coating permanently.

The readability of carbon copies depends on color and outline. Regardless of the carbon quality, copies beyond the third or fourth become progressively poorer, so that by the tenth copy all one gets is a smudge of color-with hardly any sharpness of outline. In multicopy forms, the copies below the original should be lighter-weight paper for easier transfer of the carbon. The bottom copy should be heavier paper. Because carbon smears, carbon copies should not be used for data entry copy.

Selected data are deleted from printing on certain copies by using split carbons or short carbons or by printing a random design in the area where the data will be printed. The random design blurs out the readability of the printed data. Generally, one-time carbon is preferred when a small number of copies is required. If carbon is unacceptable, NCR paper is recommended. When selected data are restricted to specific copies, split carbons are used.

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